As tampering and counterfeiting of identification documents, such as passports, driver's licenses, identification cards and badges, and documents of value, such as bonds, certificates, and negotiable instruments, increase, there is a need for greater security features and measures. Using commonly available technology, it is possible to alter such typed, printed, photographed or handwritten details in such a way that the document can then show that the ownership of that document, or an article to which that document relates, has been transferred to a party not legally entitled to that document or article. To impede the successful tampering or alteration of such details, it is a known practice to apply a security laminate over the top of such details. Such laminates may contain security features that will indicate whether the laminate itself is genuine, whether the laminate has been lifted or replaced, whether the laminate's surface has been penetrated, and whether that laminate surface has been overprinted or overlabelled. Other security features can include printing or patterns that respond to ultra-violet or infra-red light.
One example of a commercially available security laminate is the 3M™ Confirm™ Security Laminate with Floating Images, which is sold by 3M Company based in St. Paul, Minn. This security laminate with floating image is also described in U.S. Pat. No. 6,288,842 B1, “Sheeting with Composite Image that Floats,” (Florczak et al.), which is owned by the same assignee as the present application. This patent discloses microlens sheetings with composite images in which the composite image floats above or below the sheeting, or both. The composite image may be two-dimensional or three-dimensional. Methods for providing such an imaged sheeting, including by the application of radiation to a radiation sensitive material layer adjacent the microlens, are also disclosed in this patent.
A variety of security readers are known in the art. For example, U.S. Pat. No. 6,288,842, “Security Reader for Automatic Detection of Tampering and Alteration, (Mann) discloses a security reader for reading and processing information about security laminates. One example of a passport reader is commercially available from 3M Company based in St. Paul, Minn. and 3M AiT, Ltd. based in Ottawa, Ontario, Canada, as the 3M™ Full Page Reader (formerly sold as the AiT™ imPAX™ Reader).
A variety of machine vision systems are known in the art. For example, Computer Vision written by Dana Bollard and Christopher Brown is a text book concerning computer vision or machine vision. Computer Vision discloses that computer vision or machine vision is the enterprise of automating and integrating a wide range of processes and representations used for vision perception. It includes as parts many techniques that are useful by themselves, such as image processing (transforming, encoding, and transmitting images) and statistical pattern classification (statistical decision theory applied to general patterns, visual or otherwise), geometric modeling, and cognitive processing. In essence, machine vision is taking a two-dimensional representation of a three-dimensional scene and trying to replicate the three-dimensional scene. However, machine vision systems are not used for verifying the existence of a perceived three-dimensional security feature and then authenticating such security feature by comparing it to a database of security features.
Although the commercial success of available security features and security readers has been impressive, as the capabilities of counterfeiters continues to evolve, it is desirable to further improve the ability to indicate that a security feature has been tampered with or somehow compromised to help protect against counterfeiting, alteration, duplication, and simulation.